FIG. 1A is an exploded side view of a prior art package 100 that included a cylindrically-shaped prior art canister 102 and a cup-shaped prior art closure 104, which was assembled telescopically over the opened-end of prior art canister 102. Prior art closure 104 has an inside diameter that is somewhat smaller than the outside diameter of prior art canister 102. Prior art canister 102 and prior art closure 104, when assembled as shown in dotted line, combined and cooperated to form a prior art seal 106 (FIG. 1B). Prior art canister 102 included a bottom 108, generally configured as a disk, and a sidewall 110, generally configured as a cylindrical surface, coupled to and extending upwardly from the peripheral edge of bottom 108. Prior art canister 102 included an opened-end portion 112 defining an opening 129 for access from the top of prior art canister 102 to material or objects contained therein. Typically, prior art canister 102 was formed integrally, by, for example, blow-molding or injection-molding of thermoplastic material.
Prior art closure 104 included a top 114, generally configured as a disk, and a skirt 116, generally configured as an annular ring, coupled to and depending downwardly from the peripheral edge of top 114. Top 114 defined an aperture 118 (FIG. 1B) therethrough for extracting material or objects contained in prior art canister 102 from its opened-end portion 112 after assembly of prior art canister 102 and prior art closure 104. Often, prior art package 100 further included an aperture lid 120 to close off aperture 118 of prior art closure 104. In one embodiment, aperture lid 120 was coupled to prior art closure 104 by a living hinge 122, by which aperture lid 120 pivoted with respect to prior art closure 104 to close off aperture 118 of prior art closure 104. Typically, prior art closure 104 was also formed integrally, by, for example, blow-molding or injection-molding of thermoplastic material. To form a seal between aperture lid 120 and closure 104, aperture lid 120 was typically snap-fitted to closure 104 in a manner well known to one of ordinary skill in the art. Aperture lid 120 included a lid sealing ring 132 near the outer peripheral edge on the bottom surface of aperture lid 120. Lid sealing ring 132 mated with a closure sealing ring 134 formed on the top surface of closure 104 when aperture lid 120 was pivoted, snap-fitted, and placed in a closed relationship with closure 104 to form a seal.
In use of prior art package 100, material or objects for containment and packaging in prior art package 100 were first placed in prior art canister 102 through opening 129 (FIG. 1B) with prior art closure 104 removed as shown in FIG. 1A. After, the material was loaded in prior art canister 102, prior art closure 104 was telescoped or fitted over and coupled to prior art canister 102 by snap-fitting, thread-fitting, or other means well known to those of ordinary skill in the art. Moist or liquid materials where often packaged in prior art package 100. For example, moistened wipes were packaged within prior art package 100 for dispensing through aperture 118.
FIG. 1B is a partial cross-sectional side view of opened-end portion 112 of prior art canister 102 of FIG. 1A after assembly with prior art canister 102 showing prior art seal 106. FIG. 1C is a close-up view of the portion of FIG. 1B shown in dotted line and identified by reference number 1C′ showing prior art seal 106 in detail. Referring to FIGS. 1B and 1C together, the exterior surface of opened-end portion 112 of prior art canister 102 defined a sidewall groove 124, configured generally as an annular shaped indentation circumferentially about prior art canister 102. Sidewall groove 124 extended radially inwardly from and circumferentially about the exterior surface of prior art canister 102 proximate opened-end portion 112. As shown, the upper edge surface of sidewall groove 124 forms a sidewall undercut surface 126 that is beveled downwardly from its exterior to its interior indent.
The interior surface of skirt 116 of prior art closure 104 defined a skirt bead surface 128, configured generally as a peripheral flange protrusion, sometimes referred to as a bead, adjacent the bottom of skirt 116. Skirt bead surface 128 extended radially inwardly from and circumferentially about the interior surface of skirt 116 of prior art closure 104. Prior art canister 102 was assembled with prior art closure 104 by snapping skirt bead surface 128 into sidewall groove 124 whereby prior art closure 104 was retained on prior art canister 102 by means of abutting contact of skirt bead surface 128 with sidewall undercut surface 126 of sidewall groove 124.
In prior art package 100, prior art canister 102 and prior art closure 104 were further configured such that, after assembly, sidewall undercut surface 126 of sidewall groove 124 of prior art canister 102 abuttingly contacted and cooperated with corresponding skirt bead surface 128 of prior art closure 104 to form prior art seal 106. Prior art seal 106 was somewhat effective at avoiding moisture evaporation and in retaining liquid or moisture contained in prior art package 100. Prior art seal 106 slowed the loss of the liquid in the form of gaseous water vapor or other volatilized gas at the prior art seal 106 sealing interface between prior art canister 102 and prior art closure 104.
However, in the packaging industry, plastic canisters and closures often may not be accurately sized or may be out-of-round so that cooperating surfaces of the closure and canister do not properly and accurately seal. In addition, the canister and closure may be manufactured by different entities and the dimensional tolerances may vary greatly. In addition, for threaded prior art packages, to facilitate threading of the closure relative to the canister, ample thread tolerances are used, which results in axial and radial displacement sufficient to cause misalignment of the cooperating sealing surfaces. All of these variables and dimensional tolerances make it difficult to ensure a good seal in prior art packages. Poor quality seals resulted in the loss of an inordinate amount of moistening solution added to canister/closure plastic packages thereby requiring high initial moisture loading to avoid product dry-out during storage. High initial moisture loading added to over-all product cost.
In the prior art, expensive elastomeric gaskets or “O” rings were often used to provide better seals that slowed moisture loss from the package. In addition, well-known but expensive secondary seals, such as induction seals or heat seals, were often used in prior art packaging to retain moisture during distribution and in-store or user storage before product use.